Reproduction of impressions by means of stamping with metal dies equipped with suitable impressions, or embossing, has been widely practised for gold coins and commemorative medals.
In recent years, the public has shown interest in purchasing gram-quantities of gold, which created a new market in precious metal gifts and souvenirs. However, the traditional embossing techniques applicable to coins and medals are not suitable for thin strip or sheet materials, typical of the new market, and the products produced by such techniques generally lacked aesthetic appeal as gifts and souvenirs.
Therefore, it would be of great interest to be able to emboss by roll forming appropriate impressions on the surface of thinly-rolled strip materials. For example, a one gram piece of gold can be rolled into an attractive foil material of 20 micrometers thickness which is a candidate material for such roll-embossing operations.
However, such embossing/marking operations are difficult to perform on such thin materials, because they lack mechanical strength, and easily suffer from mechanical damages during production and handling operations.
Furthermore, gifts and medallions are usually custom made for a large number of small-lot customers, and the high cost of metal dies makes it uneconomical to produce such items by roll-embossing.
In such instances, a composite material, consisting of a precious metal foil backing and a separate transparent acrylic plate having suitable preset patterns or designs, may provide an attractive alternative production method to roll-forming or stamping operations.
In this case, the precious metal foil can be mass produced while various decorative plate having preset custom markings can be produced in small lot quantities. The difficulties of handling thin foil materials remain as well as the difficulties associated with processing a composite assembly, however.